One of the most important findings in cognitive psychology relates to memory. Often, we think of memory as storing information in a hard drive within our brain, retrieving it wholesale when we need to. But this is in fact far from the truth: experiments have shown that we don’t quite store information in its entirety; instead, we only distill and then store the gist of it. When we need this information afterward, we reconstruct (as opposed to retrieve) the memory.
Here’s a common trick from Dan Gilbert’s Stumbling on Happiness, a truly wonderful read on how we often fail to predict what makes us happy:
Read the list of words below, and when you’ve finished, quickly cover the list with your hand. Then I will trick you.
Here’s the trick. Which of the following words was not on the list? Bed, doze, sleep, or gasoline? The right answer is gasoline, of course. But the other right answer is also sleep, and if you don’t believe me, you should lift your hand from the page. If you’re like most people, you knew gasoline was not on the list, but you mistakenly remembered reading the word sleep. Because all the words on the list are so closely related, your brain stored the gist of what you read (a bunch of words about sleeping) rather than storing every one of those words. Normally this would be a clever and economical strategy for remembering, The gist would serve as an instruction that enabled your brain to reweave the tapestry of your experience and allow you to ‘remember’ reading the words you saw. But in this case, your brain was tricked by the fact that the gist word – the key word, the essential word – was not actually on the list. When your brain rewove the tapestry of your experience, it mistakenly included a word that was implied by the gist but had not actually appeared.
As for me, I’d seen this trick before; but when I read the book, I fell for it once again.